‘We just want to show what is happening to the climate’

Is it warmer or colder today than average for the time of year? To answer this question, the KNMI, the Royal Netherlands Meteorological Institute, compares the temperature to the average over a long period. That period is 30 years and is regarded as ‘normal’. The period 1991-2020 just replaced the previous ‘normal’ of 1981-2010. Meteorological services such as the KNMI shift the reference period by one decade every 10 years.

However, third year technology management student Dennis Botman (TPM) and three other social entrepreneurs do not believe that the average over this period should be considered normal. They designed a weather app called ThermoMate that goes much further back in time, namely to 1950. ThermoMate compares today’s temperature with the average of the last 70 years. If you open the app, you see the temperature at that point in time in that particular location, how much warmer or colder it is than average, and which cities in Europe normally experience such temperatures.

Why did you opt to compare today’s temperature with that of the last 70 years instead of the last 30 years?
“If you move the reference period up as time passes, as the KNMI does, you are sweeping part of climate change under the carpet. If you only look from 1980 onwards, the Netherlands was 1.3 degrees warmer on average than ‘normal’ in 2020. But if you compare it to 1950, it was 1.9 degrees. That is a big difference. The app shows the real climate change better and makes it more difficult for climate sceptics to downplay global warming.”

Is 1950 not also an arbitrary date?
“No, because it was around then that the Netherlands first had nationwide weather station coverage. And 1950 is also not that long ago that people can’t imagine what it was like.”

What do you hope weather app will do?
“Make people more aware of climate change. People talk about the weather for about eight minutes a day. Less now of course that they are not meeting up at the coffee machine, but normally it’s a common subject of conversation. We believe our app can link the short term – the weather every day – to the long term – the climate. We do not want to wag our finger and say that you should not fly or eat meat anymore. We just want to show what is happening to the climate. If you see that over the last seven days it has been just as warm here as in a South European city, the message will come across.”

Are people already using the app?
“A couple of thousand are. The number is going up.”

Will it have any new features at some point?
“We may include information about precipitation in the app. We are thinking about it now.”